1. Field of the Invention
The present invention relates to a laser light-source apparatus and a projector apparatus.
2. Description of the Related Art
Recently, it is proposed that a laser light source is used as a light source for a projector apparatus. The laser light source has such advantages, for example, as that it has a color reproduction range wider than an extra-high pressure mercury lamp, which is used in conventional projector apparatuses; that it can instantly illuminate; that it has a low power consumption; and that it has a long product life.
Along with downsizing and weight reduction of projector apparatuses, while a light source also needs to satisfy a similar requirement, an amount of light to be supplied has increased for a shift to a larger screen and a higher intensity of a projector device, so that improvement in heat-radiation efficiency of a light source is made an important technical task. Moreover, because the laser light source varies its emitted-light wavelengths and its laser outputs depending on a change in temperature of a light emitting unit, it needs to achieve stabilization of laser output by appropriately cooling in accordance with specifications of the light emitting unit.
For this reason, in addition to a conventional air-cooling system, it is desirable to employ a liquid cooling system to increase heat-radiation efficiency by circulating a coolant. Furthermore, in order to improve the cooling efficiency, it is desirable to include a cooling structure that a plurality of laser-light emitting units are arranged in a layout on a driving substrate, heat release from each light emitting unit is distributed, and each light emitting unit is kept at an optimal temperature.
For downsizing and heat release of a laser light-source apparatus, an apparatus in which a semiconductor laser light-source module is installed on a driving circuit board is proposed in Japanese Patent Application Laid-open No. H7-178957. A method disclosed in FIG. 1 and page 1 of this Patent Document No. H7-178957 is a method of releasing heat by mounting a semiconductor laser light source on a metal pattern on a substrate.
However, according to the above conventional technology, there is a problem that when a laser output is high and the amount of heat generation is increasing, heat radiation with a metal pattern on a substrate is insufficient, so that it is difficult to keep a heat generating unit at an optimal temperature.